Spring Config: Using @ConfigurationProperties to inject maps does not work

[Sgitario]

Describe the bug

Spring users can bind maps like this:

@ConfigurationProperties("maps")
public class MapWiringProperties {

    // Cover injection of maps of integers and strings;
    public Map<Integer, String> integers;

    // Cover injection of maps of string and classes
    public Map<String, Person> persons;

    public static class Person {
        public String name;
        public int age;

        @Override
        public String toString() {
            return String.format("person[%s:%s]", name, age);
        }
    }
}

With application.properties:

maps.integers.1=Value 1
maps.integers.2=Value 2

maps.persons.character1.name=Sarah
maps.persons.character1.age=19
maps.persons.character2.name=Terminator
maps.persons.character2.age=999

If we try to use the same using the spring properties Quarkus extension, it throws the following exception:

Caused by: java.lang.IllegalArgumentException: SRCFG00013: No Converter registered for interface java.util.Map

Expected behavior

Not sure if this is very complex to mimic in the Quarkus extension (we should generate the equivalent object using the @ConfigMapping annotation.
However, if this is too complex to support, we should document the current limitations in the Spring properties guide.

Actual behavior

No response

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

No response

Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @geoand

[geoand]

This is a known limitation of @ConfigProperties. We should just print a more relevant error message.

I'll do that when I get back from PTO